1. Field of the Invention
This invention relates to fixed troughs and deflectors of the type used to convey gobs of molten glass from an oscillating chute of a gob distributor to a blank mold of an I.S. machine.
2. Description of the Prior Art
In the manufacture of glass containers by a machine of the I.S. type, gobs of molten glass are repetitively delivered to a fixed delivery system for each machine section by a chute of an oscillating gob distributor that oscillates between the delivery systems of the various sections of the I.S. machine, which are aligned side-by-side. Each gob delivery system includes an elongated, downwardly inclined trough, which typically has a cross-sectional configuration of an upwardly facing U whose sides taper outwardly with respect to one another, and an elongated, curved and downwardly inclined distributor, which typically has a cross-sectional configuration of a downwardly facing U whose sides taper outwardly with respect to one another. Typically, the sides of each trough have a 20.degree. included angle therebetween, and the sides of the deflector have an included angle of 12.degree. therebetween. U.S. Pat. No. 4,772,306 (Davey et al.), the disclosure of which is incorporated by reference herein, describes a prior art version of a glass gob delivery system of this general character.
Problems have been identified with prior art glass gob delivery devices as described above with respect to proper centering of the gob within the devices as the gob travels from the distributor to an I.S. machine section, specifically to a blank mold station thereof. The use of tapered sides in the trough and in the deflector is intended to assist in centering the gob within the trough and deflector prior to its introduction into the blank mold of the I.S. machine, but can also lead to some degree of "bobsledding" of a gob as it is enroute to the I.S. machine section blank mold. In this case the gob will not be properly centered and aligned with the blank mold as it enters an opening at the top of the blank mold (which corresponds to the bottom of a container to be formed from a parison formed in the blank mold because the parison is formed in the blank mold in an inverted orientation, as is known in the art). To deal with the problem of a gob entering a blank mold in a misaligned or miscentered condition it has been known to lubricate the interior of the blank mold by periodically swabbing it with a mold dopant substance, but this is a labor intensive practice, which is desirably eliminated whenever possible.
Another problem encountered with prior art glass gob delivery systems is that they have heretofore been formed from steel or cast iron, to be able to resist the thermal effects from contact with the molten gobs passing therethrough. Troughs and deflectors formed from an aluminum alloy would provide for better cooling of the items of the delivery equipment.
Another problem encountered with prior art glass gob delivery systems is that gobs can fall or partly fall from the deflectors thereof if they do not have sufficient velocity when they enter the curved, downwardly facing deflectors unless suitable covers are provided for such deflectors. However, such deflector covers tend to limit the size of the gobs passing through the deflector, thus necessitating frequent replacement of deflectors to accommodate gobs of different size when the molds of the I.S. machine are changed to produce containers of a different size.